The main thesis we will address is that oxidants of oxidation reactions promote cell proliferation and conversely, that reductants are capable of suppressing cell growth of both normal and malignant cells. We will focus our experiments on the plasma membrane and contractile structures which may be membrane associated such as microfilaments and microtubules. We will examine the stimulation of lymphocytes and contact inhibited cell proliferation with various oxidants including periodate, H2O2 and diamide, a specific oxidant of reduced glutathione. Conversely, we will examine the ability to suppress proliferation of lymphoid cells, contact inhibited cells, and perhaps more importantly, malignant or transformed cells with various thiol reductants. We will assess the actions of the redox agents in studies which will employ a variety of morphological techniques examining intrinsic membrane structure, membrane receptors and dynamic alterations of these components. We will further attempt to examine by electron microscopy dynamic alterations in the cell surface sites that periodate is oxidizing which may play a causal role in the ensuing proliferation. In addition to a possible cell surface mode of action of these redox agents, we will examine the possible effect of these agents on cytoplasmic contractile elements such as microfilaments and microtubules using thin section electron microscopy. Our previous studies in the 3T3/SV3T3 system, along with those of other laboratories, have implicated perturbations of these structures in cells that appear to have lost growth restriction. Lastly, we will examine the role of serum and a specific serum fraction we have indications that may be either mediating or overriding the cellular response to redox agents.